- From: Alex Danilo <alex@abbra.com>
- Date: Fri, 25 Feb 2011 11:30:13 +1100
- To: Rik Cabanier <cabanier@gmail.com>
- Cc: Anthony Grasso <Anthony.Grasso@cisra.canon.com.au>, Dean Jackson <dino@apple.com>, Alistair MacDonald <al@bocoup.com>, Rik Cabanier <cabanier@adobe.com>, Cameron McCormack <cam@mcc.id.au>, Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>, "public-fx@w3.org" <public-fx@w3.org>
Hi Rik, Fair enough. In SVG to isloate that, you'd use: <g enable-background="new"> which isolates the blending to that group, then uses a plain 'over' to alpha blend the result to the background. Alex --Original Message--: > >Hi Alex, > >The 'blend: layer' makes it so that only the graphic of group A are used when the multiply blend on B is calculated. > >Rik > >On Thu, Feb 24, 2011 at 4:13 PM, Alex Danilo <alex@abbra.com> wrote: > >Hi Rick, > > Yes, that's correct. In SVG as specified, it could be ><g comp-op="multiply">...</g> or use inline style as you wrote >or applied to individual objects, etc. Although, there's no real >need for 'blend:layer' in your example, but the overall idea is >right. > >Alex > >--Original Message--: > >> >> >>Hi Alex, >> >> >> >> >>to make sure I'm not confused. >> >> >>This is a filter: >> >><svg version="1.1" xmlns="http://www.w3.org/2000/svg"> >> <defs> >> <filter id="srcLoadedOverlay"> >> <feImage xlink:href="url(#canvas0)" result="img1" /> >> <feImage xlink:href="url(#canvas1)" result="img2" /> >> <feImage xlink:href="url(#canvas2)" result="img3" /> >> <feBlend in="img1" in2="img2" result="blend1" mode="multiply" /> >> <feBlend in="blend1" in2="img3" mode="lighten" /> >> </filter> >> </defs> >></svg> >> >>and this would be a property: >> >><html> >> >>... >> >><body> >> >>.... <- backdrop >> >><div style="blend: layer;"> <- group A >> >> ... <- text, images, etc >> >> <div style="blend: multiply;"> <- group B >> >> .. <- text, images, etc >> >> </div> >> >></div> >> >>Rik >> >>On Thu, Feb 24, 2011 at 3:53 PM, Alex Danilo <alex@abbra.com> wrote: >> >>Hi Anthony and all, >> >>--Original Message--: >>>Just adding to what Alex said (see below)... >>> >>> >>>>-----Original Message----- >> >>>><snip/> >>>> >>>>Perhaps that should serve as something to look at. This was researched >>>>extensively at the time, and a property works far better than the SVG >>>>filter mechanism when combining a lot of objects for blending. >>>> >>> >>>This is because the background is included twice when using filters to perform compositing. This leads to incorrect results - the output tends to be darker than expected. >> >>Ignoring side-effects, one of the main advantages of a property >>over a filter is no need for any sort of intermediate bitmap. >> >>The object being blended can be rasterized and alpha blended >>with the correct blend mode directly to the canvas. So the >>performance is significantly higher, especially if you are >>trying to composite lots of graphics on top of live HD video >>where memory bandwidth actually matters. >> >>Alex >> >> >> >> >> > > > > >
Received on Friday, 25 February 2011 02:09:42 UTC